In regards to your concern about power, I drove Studio 100s in a surround setup for about a year with a Proceed Amp-5. At 125 watts per channel, the 100s could be driven to quite loud listening levels. Unless your room is quite large, the 100s at 89 dB sensitivity should provide fairly enjoyable volumes with a 150 watt/channel amp.
My opinion, for what it's worth.
My opinion, for what it's worth.